<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>

    <style>
        div{
            width: 200px;
            height: 200px;
            background-color:white;
            transition:all 2s ease-in 0s;
            margin: auto;
        }
        
        div:hover{
            border-radius: 50%;
            box-shadow: inset 30px 30px 30px 30px gray;
        }

    </style>
</head>

<body margin:auto>
    <div ></div>
    
</body>
</html>